Motorola MVME172 IP Clock Register, Setting IP32 to a one enables the IndustryPack bus to

4

IP2 Chip

IP Clock Register

ADR/SIZ					$FFFBC01D (8 bits)
BIT	7	6		5		4	3	2	1	0
NAME	0	0		0		0	0	0	0	IP32
OPER	R	R		R		R	R	R	R	S
RESET	0 R	0 R		0 R		0 R	0 R	0 R	0 R	0 R
	IP32		Setting IP32 to a one enables the IndustryPack bus to
			operate synchronously with the MC68060 local bus clock.
			Setting it to a zero will enable 8 MHz operation. In this

mode, the IndustryPack bus cycles and MC68060 local bus cycles operate asynchronously.

The IP32 bit controls clock synchronization logic. It does not change the clock frequency on the bus. Jumper J11 on the 200/300-Series MVME172, and Jumper J14 on the 400-/500-Series, control the IP bus clock source. If J11 (200/300-Series) or J14 (400/500-Series) pins 1 and 2 are jumpered, then the IP clock source is set to 8 MHz. For this setting, IP32 control bit must be a zero.

If pins 3 and 2 are jumpered, then the IP clock source is set to be synchronous with the MC68060 local bus clock. This clock may be 25 MHz, 30 MHz, or 32 MHz depending on the model. For this setting, IP32 control bit must be a one.

Note For some early versions of the 200/300-Series MVME172, J11 is factory hardwired to the 8 MHz position (pins 1 and 2 connected). If the 32 MHz option is desired, remove the staple between pins 1and 2 and install a jumper between pins 2 and 3. The person performing this work must ensure that the MVME172 is ESD (Electro Static Discharge) protected.

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